This invention relates generally to a securing device, and more particularly to a cord securing device that guards against accidental or inadvertent disconnection of connected electrical cords and the like.
In many industrial and commercial environments, it is often useful to serially connect a number of electrical extension cords, or to connect an extension cord to an electrical device. In the home or office environment, plugs of electrical power cords for equipment such as vacuum cleaners, electric-powered lawn mowers, drills, lights, computers, and the like, are often coupled to receptacles and/or extension cords. The friction connections between coupling prongs of the plugs and the blades of the receptacles vary greatly and generally will not hold the cords together against anything more than moderate separation tugs. Similarly, in the commercial or industrial environment, tools are commonly connected by extension cords. At construction sites, these cords are often exposed to dust, mud and moisture and may be subject to significant separation tugs.
The inadvertent complete or partial separation of a plug from a socket is not only annoying, but can be dangerous. Particularly in industrial and commercial environments, if the plug and socket combination inadvertently disengages during use, such disconnection can cause down time and a potential safety hazard depending on the type of equipment the power was cut off from. Even if partial separation occurs, a short circuit could occur and result in a fire or shock.
Carpenters and others have often attempted to solve this separation problem by tying two cords together in a knot. This method is unsafe because it can weaken or break one or both of the cords at the cord ends, creating an electrical hazard. Additionally, knots snag when moving cords around corners and other objects. Tape has also been used to hold cords together. Although somewhat effective, it is often messy because it leaves a residue of adhesive on the connectors after the tape has been removed, and does not allow for quick or easy disconnection. Thus, different types of clips have been developed for securing two cords together, such as the ones disclosed in U.S. Pat. No. 6,012,940 to Wheeler, and U.S. Pat. No. 4,183,603 to Donarummo. These clips are generally a unitary piece of plastic that clips around each cord. However, such clips cannot be used to connect a power cord to an electrical outlet on a wall, are cumbersome, and not very effective in preventing partial separation.
A number clamps have also been developed for securing a power cord to an extension cord, such as the ones disclosed in U.S. Pat. No. 6,135,803 to Kovacik et al.; U.S. Pat. No. 5,732,445 to Stodolka, et al.; U.S. Pat. No. 5,328,384 to Magnuson; and U.S. Pat. No. 4,957,450 to Pioszak. Relatively simple clamps are generally constructed of a plastic strip that is held together with a hook-and-loop material or snap-fit. However, such devices become useless once the hook and loop material becomes too dirty to provide a reliable bond. Relatively complex clamps are generally constructed of two parts that lock together with a screw mechanism. While such clamps may be more reliable for some uses, they still have the drawback of being difficult to use if they become dirty. At construction sites, power cords often lay on the bare ground and can become caked with dirt and mud. Even if they remain clean, these clamps are often time consuming to attach and require manipulation of several parts, making them complicated to manufacture and difficult to use. Further, some of these clamping devices only work if they are attached to the cords during the manufacturing stage of the cord itself. Others must be detached from the cords if not in use, and therefore need to be moved when switching cords from one connection to another.
Devices or adapters with multiple electrical sockets have also been developed in an attempt to solve the inadvertent separation problem, such as the one disclosed in U.S. Pat. No. 5,931,702 to Fladung. The Fladung device can only secure one power cord to one extension cord (i.e. one male connection to one female connection). Thus, if there are five female connections and one male connection, only one female connection and one male connection are secured. Four of the five cords can still be inadvertently separated from the adapter. Further, the device requires the electrical cord to be pulled through an eyelet and wrapped about a post. This presents the same problems as tying a knot in the cord.
Other devices have been developed for securing a plug to an electrical wall outlet, such as the one disclosed in U.S. Pat. No. 4,457,571 to Lavine et al. The Lavine device consists of a cup-like housing that is open on the top and one side. The open side has flanges that slidingly engage slots on the face plate of a wall outlet. However, these devices require permanent attachment to wall outlets, forcing the user to purchase multiple sets. The separate parts for these devices could become lost, and if the housing is left on the receptacle while not in actual use, small children may be tempted to put small toys or liquids into the housing. Further, these devices will not work in conjunction with an extension-cord-to-power-plug connection.
Accordingly, a need exists for an easy to use, compact, and streamlined device that can prevent inadvertent disengagement of a cord from a wall outlet, an extension cord, a power strip, or other connection source.
The present invention relates to a cord securing device. As described in more detail below, and shown in the accompanying drawings, the cord securing device of the present invention uses mechanical means to apply a clamping force between mating electrical contacts to lock conventional plugs into the female end of one embodiment of the device. This clamping force may be applied by the female end by providing a force against the male prong in any number of directions. For example, in a female device designed to retain a two-pronged male plug, the force could be provided between the two prongs and directed outwardly such that each prong is clamped. Similarly, a clamping force is used to lock the male prongs of another embodiment of the device to a socket. The clamping force may be provided by moving the prongs in any number of directions. For example, in a male device having three prongs, two prongs could be stationary and the third prong forced inwardly toward the two other prongs so as to clamp the prongs in the socket.
The securing device of the present invention may be incorporated into a variety of embodiments. One embodiment is a compact adapter that can be used to lock a conventional power cord to an extension cord, wall receptacle or the like. This embodiment includes a female receptacle combined with a male plug. The adapter has a housing that supports three prongs, i.e. hot, neutral and ground prongs. The hot and neutral receiving prongs include sleeves that are designed to clamp a male plug inserted into the adapter. This xe2x80x9cclampingxe2x80x9d or locking function is selectively obtained by moving a screw-style plunger against ramps on the side of the receiving prong that engages the prongs of the male plug. The screw-style plunger is generally a screw member that moves within the housing. In this embodiment, the screw-style plunger is accessible from the male side of the adapter and moved by rotating it with a screwdriver or the like. The screw-style plunger pushes against the ramp on each receiving prong thereby pushing them outward. The end of the receiving prong that is on the outside is held in place thereby sandwiching the male plug prong in place. The male portion of the embodiment uses a another type of plunger (xe2x80x9csleeve-stylexe2x80x9d plunger) to apply pressure against the ground prong. The ground prong has a ramp located on one edge. The sleeve-style plunger slidingly engages the ramp when it is moved by a wheel that is threadingly engaged thereto. When the sleeve-style plunger moves up the ramp, the exposed portion of the ground prong moves downwardly toward the protruding portion of the hot and neutral prongs. This position of the ground plug serves to grip the wall outlet or other receptacle into which the adapter is plugged.
In other embodiments, the female receptacle uses a sleeve-style plunger that is moved by rotating a wheel that surrounds the housing. This is especially useful for devices where it is not easy or possible to access the screw-style plunger from a surface opposite from where the outside plug is inserted. Thus, one embodiment of the present invention is an extension cord where the male portion of the invention is separated from the female portion of the invention by a cord.
Another embodiment of the present invention is a power strip. On the body of the power strip is a row of the female receptacles. Each receptacle can be locked by turning the threaded wheel corresponding to the female receptacle. If desired, the male plug of the present invention is used to connect the power strip to a power source, and is connected to the body by a cord. The power strip may incorporate surge-protecting or power-converting features if desired in a particular application.
The male portion of the present invention can be installed on electric devices as original equipment during manufacture or as a replacement plug by a consumer. Thus, one embodiment of the present invention is a hand tool, such as a drill, that incorporates the male plug of the present invention. Another embodiment of the present invention is an appliance such as a vacuum cleaner that incorporates the male plug of the present invention. Additionally, the male plug or female receptacle can be sold as a kit for replacing conventional plugs and receptacles.
The female receptacle of the present invention that is locked by turning a wheel can also be used in conjunction with various adapters. One such embodiment is an adapter that has one male plug wheel and one female receptacle wheel. The male plug and female receptacle are separated by an elongated housing. Each is locked by turning the separate wheel corresponding thereto, which causes the corresponding plunger to move accordingly. Another such embodiment is a multi-access adapter that has a T-shaped, or other shape housing. In this embodiment, there is one male plug extending from the housing, and at least two other female receptacles extending from the housing.
While the present invention is particularly useful in connecting electrical plugs together, other applications are possible and references to use with power cords and certain electrical devices should not be deemed to limit the application of the present invention. The present invention may be advantageously adapted for use where similar performance capabilities and characteristics are desired. These and other objects and advantages of the present invention will become apparent from the detailed description, claims, and accompanying drawings.